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MotivationsExploring new p-type semiconductor nanoparticles alternative to thecommonly used NiO is crucial for p-type dye-sensitized solar cells (p-DSSCs) to achieve higher open-circuit voltages (Voc). Delafossite CuGaO2 has a lower valence band maximum(VBM)compared to NiO and therefore could provide a larger Voc in p-DSSCs. In contrast to the dark colored NiO, the CuGaO2 nanoplates are whitebecause of the large band-gap. Therefore, the porous films made of thesenanoplates barely compete with the dye sensitizers for visible lightabsorption. Proprietary and Confidential 2 American Chemical Society

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CuGaO2 nanoplate’s thermal-stabilityIt’s important to make sure that CuGaO2 won’t decompose during the thermal-treatment in the solar cell fabrication process because of the existence of Cu+.The X-ray diffraction(XRD) pattern showed that CuGaO2 is thermo-kineticallystable when heated below 350oC. Proprietary and Confidential 4 American Chemical Society

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CuGaO2-DSSCs J-V performanceA Voc as 357mV in Co3+/2+(dtb-bpy) electrolyte was achieved and it’s among thehighest values that have been reported. More research is undergoing to increase the current intensity. Proprietary and Confidential 6 American Chemical Society

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Conclusion We report the first application of light- colored CuGaO2 nanoplates in p-DSSCs that produce high photovoltages. A Voc of 357 mV has been achieved with a Acknowledgments Co3+/2+(dtb-bpy) electrolyte under 1 Sun The authors acknowledge the AM 1.5 illumination. And more funding support from the U.S. remarkably, a saturation photovoltage of Department of Energy (Award 464 mV has been achieved with the No. DE-FG0207ER46427). increasing illumination intensity.Proprietary and Confidential 7American Chemical Society